co-responsible, someone jointly with somebody else
“Como ya sabemos, el art. 20 somete la totalidad de las cuestiones que pudieran suscitarse en el marco de la acción de regreso al ordenamiento aplicable a la obligación del corresponsable que satisfizo a la victima e impediría oponer a sus destinatarios cualquier medio de defensa contemplado en el ordenamiento que regule su obligación con el acreedor.” — As we already know, article 20 [of the Rome II Regulation] submits the totality of the questions that could arise in the context of recourse actions to the legal system applicable for the obligation of the co-obligor who has satisfied the victim and forestalls putting up any means of defence against his destinataries provided in the legal system governing his obligation to the creditor.
From co- + responsable.